Tag: weightlessness

ISS research suggests weightlessness accelerates aging in stem cells

8:58 am

According to a study that flew stem cells on four separate missions to ISS ranging in length from 32 to 45 days, weightlessness appears to age stem cells significantly.

Researchers from University of California San Diego Sanford Stem Cell Institute have discovered that spaceflight accelerates the aging of human hematopoietic stem and progenitor cells (HSPCs), which are vital for blood and immune system health. In a study published in Cell Stem Cell, the team used automated artificial intelligence (AI)-driven stem cell-tracking nanobioreactor systems in four SpaceX Commercial Resupply Services missions to the International Space Station (ISS) to track stem cell changes in real time. The findings show that the cells lost some of their ability to make healthy new cells, became more prone to DNA damage and showed signs of faster aging at the ends of their chromosomes after spaceflight — all signs of accelerated aging.

Upon return to Earth the study also found the cells recovered somewhat.

You can read the peer-reviewed paper here.

In a sense, this study confirms what numerous other research has found, that weightlessness mimics the conditions of old age, and causes the same physical decline seen in the elderly. It also shows that much of that damage in weightlessness is transient, recovering upon return to Earth.

This research once again highlights the imperative need to study the impact on various levels of artificial gravity on the human body. Will producing a 10% g environment — using centrifugal force — mitigate these negative impacts? Or will we have to simulate a full 1 g environment? Or something in between?

The first option is much easier in terms of engineering. The last will be complex and take time to develop.

At the moment almost no research has been done in this area. And it needs to happen soon, if people intend to go to Mars in the near future. Such journeys, six months minimum in weightlessness, are likely to leave the passengers somewhat debilitated upon arrival, no matter how much they exercise along the way. And being debilitated is not a good condition for a pioneer trying to build a new civilization on an alien world.

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Update on eye research at ISS

10:03 am

Link here. The NASA update provides a nice overview of the research, beginning with this overview:

When astronauts began spending six months and more aboard the International Space Station, they started to notice changes in their vision. For example, many found that, as their mission progressed, they needed stronger reading glasses. Researchers studying this phenomenon identified swelling in the optic disc, which is where the optic nerve enters the retina, and flattening of the eye shape. These symptoms became known as Space-Associated Neuro-Ocular Syndrome (SANS).

The research suspects the changes are due to the fluid shifts in the body that take place due to weightlessness, with blood shifting from the legs to the head. Various projects have studied a number of solutions, including wearing leg cuffs, administering vitamin B, and possibly using centrifuge-created artificial gravity to mitigate the condition. The problem has also generated new work in developing better equipment for to studying the eye, including improved imaging and techniques for measuring the eye’s stiffness.

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Bioengineered heart samples on ISS confirm that weightlessness weakens and ages the heart

9:33 am

Using 48 bioengineered heart samples that spent 30 days on ISS in 2020, scientists have confirmed other research that showed weightlessness not only weakens the heart, it ages it as well.

In addition to losing strength, the heart muscle tissues in space developed irregular beating (arrhythmias)—disruptions that can cause a human heart to fail. Normally, the time between one beat of cardiac tissue and the next is about a second. This measure, in the tissues aboard the space station, grew to be nearly five times longer than those on Earth, although the time between beats returned nearly to normal when the tissues returned to Earth.

The scientists also found, in the tissues that went to space, that sarcomeres—the protein bundles in muscle cells that help them contract—became shorter and more disordered, a hallmark of human heart disease. In addition, energy-producing mitochondria in the space-bound cells grew larger, rounder and lost the characteristic folds that help the cells use and produce energy.

Finally …[t]he tissues at the space station showed increased gene production involved in inflammation and oxidative damage, also hallmarks of heart disease.

None of this is ground-breaking, as it confirms numerous other past studies. What it does do however is confirm that long-term weightlessness is not good for a person’s heart. Many studies have shown that these issues mostly go away once astronauts return to Earth, but for any journey to Mars, involving two years in weightlessness, this data suggests the health risks will be far higher.

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Centrifuge research on ISS suggests some artificial gravity can mitigate negative effects of weightlessness

1:30 pm

Two of the three centrifuges on ISS

When I appeared on the Space Show last month I stated something about centrifuge research that was wrong. I had been under the false impression that no such research had yet been done on ISS, and our only data came from one experiment performed by the Soviets on one of their early space stations decades ago.

Charles Lurio, who writes the very respected Lurio Report newsletter on space matters, called me afterward to correct me, and then followed up by sending me a link to a paper describing research on ISS in the past few years using rats inside three different small centrifuges (two of which are shown in the picture to the right). For this information I thank him.

You can download the paper here [pdf]. The research is significant because it suggests that the medical problems of weightlessness can be solved by creating an artificial gravity far less the Earth’s 1g environment. From the paper’s abstract:
» Read more

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Study: Long periods of weightlessness caused changes in the brain

9:55 am

Scientists studying the brains of 30 astronauts who spent from two weeks to one year on ISS have found that the longer a person stayed in weightlessness the greater the changes caused in the brain, and the longer it takes to recover.

Their findings, reported today in Scientific Reports, reveal that the brain’s ventricles expand significantly in those who completed longer missions of at least six months, and that less than three years may not provide enough time for the ventricles to fully recover.

Ventricles are cavities in the brain filled with cerebrospinal fluid, which provides protection, nourishment and waste removal to the brain. Mechanisms in the human body effectively distribute fluids throughout the body, but in the absence of gravity, the fluid shifts upward, pushing the brain higher within the skull and causing the ventricles to expand.

“We found that the more time people spent in space, the larger their ventricles became,” said Rachael Seidler, a professor of applied physiology and kinesiology at the University of Florida and an author of the study. “Many astronauts travel to space more than one time, and our study shows it takes about three years between flights for the ventricles to fully recover.”

You can read the paper here. The expansion of ventricles is a normal process due to aging, but I could not find any description in the paper noting its impact, for good or ill. Long periods of weightlessness brings it about quickly, but only temporarily.

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Research: Flies on ISS benefited greatly from simulated gravity

10:52 am

Scientists have found that providing fruitflies 1g of artificial gravity on ISS using a centrifuge acted to reduce the medical changes that weightlessness produces.

In this study, scientists sent flies to the space station on a month-long mission in a newly developed piece of hardware called the Multi-use Variable-gravity Platform (MVP), capable of housing flies at different gravity levels. The flies in this hardware had access to fresh food as they lived and reproduced. By using distinct compartments, the MVP allowed for different generations of flies to be separated. On the space station, one group of fruit flies experienced microgravity similar to their human counterparts. Another group was exposed to artificial gravity by simulating Earth’s gravity on the space station using a centrifuge – an instrument that spins to simulate gravity. While on the space station, cameras in the hardware recorded behavior of these “flyonauts”. At different points in time, some of the flies were frozen and returned to Earth to study their gene expression.

…More in-depth analysis on the ground immediately post-flight revealed neurological changes in flies exposed to microgravity. As the flies acclimated to being back on Earth after their journey, the flies that experienced artificial gravity in space aged differently. They faced similar but less severe challenges to the flies that were in microgravity.

You can read the paper here.

To some extent, this study tells us nothing. We already know from a half century of research that zero gravity causes negative physical changes in both fruit flies and humans. What we really need to know is the lowest level of artificial gravity that would be beneficial. It is much easier to engine a spacecraft to produce 0.1g of artificial gravity than 1g. Even 0.5g would ease the engineering problem. The problem is that we do not yet know the right number.

It is a shame the scientists didn’t subject some flies to 0.5g, just to find out if that level of artificial gravity worked to provide benefits.

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New research confirms long term bone loss during long missions in weightlessness

9:46 am

According to new research done on ISS, scientists have confirmed what Soviet-era scientists had learned back in the 20th century, that long term bone loss during long missions in weightlessness can take many months to recover once back on Earth.

The bone density lost by astronauts was equivalent to how much they would shed in several decades if they were back on Earth, said study co-author Dr Steven Boyd, of Canada’s University of Calgary and director of the McCaig Institute for Bone and Joint Health.

The researchers found that the shinbone density of nine of the astronauts had not fully recovered after a year on Earth – and they were still lacking about a decade’s worth of bone mass. The astronauts who went on the longest missions, which ranged from four to seven months on the ISS, were the slowest to recover. “The longer you spend in space, the more bone you lose,” Boyd said.

The study also confirmed that some exercises in space helped to mitigate the bone loss, which ranged from 1% to 2% per month. No exercises prevented it however.

For missions to Mars, the bone loss appears less of an issue than the loss of muscle strength. Even with extensive bone loss after six months to a year in space astronauts do not notice this loss when returning to Earth gravity. They will certainly not notice it on Mars, with a gravity field 39% that of Earth’s.

More concerning is the loss of muscle strength during long missions in weightlessness. After six months to a year in weightlessness astronauts struggle on Earth to walk after first landing. This is why they are helped immediately placed to chairs upon return. On Mars no such help will be available.

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Study: Russian astronauts on ISS have better techniques for protecting the brain

9:12 am

According to a study comparing the changes in the brain experienced during long term missions on ISS, it appears that the Russians have developed better protocols for preparing themselves for return to Earth that prevents the enlargement in one part of the brain seen in American astronauts.

From the link:

The study focused on 24 Americans, 13 Russians, and a small, unspecified number of astronauts from the ESA. The researchers collected MRI scans of the astronauts’ brains before and after they spent six months on the ISS (only 256 individuals have visited the space station).

After being in space, all the space travelers exhibited similar brain changes: cerebrospinal fluid buildup and reduced space between the brain and the surrounding membrane at the top of the head. The Americans, however, also had more enlargement in the regions of the brain that serve as a cleaning system during sleep, e.g. the perivascular space (PVS).

…The Russian astronauts did not exhibit enlarged PVS, suggesting there might be differences in protocol that are neuro-protective.

From the paper itself:

[Russian C]osmonauts undergo six lower body negative pressure (LBNP) sessions starting two weeks prior to landing, while NASA and ESA astronauts do not typically do it. LBNP induces caudal displacement of fluids from the upper body by placing the legs and pelvis in a semiairtight chamber with negative pressure.

An advanced resistive exercise device (ARED) is regularly used by space flyers to perform free weight exercises on the ISS, but the load and frequency of use are lower for [Russian] cosmonauts compared with NASA and ESA astronauts. Lifting heavy loads during resistive exercise is often accompanied by a brief Valsalva maneuver, inducing increased ICP and decreased cerebral blood flow and cerebrovascular transmural pressure, which can result in PVS fluid accumulation. Although the effects of LBNP and ARED on the brain during spaceflight are unknown, they could partly explain the different WM-PVS changes detected in astronauts and cosmonauts. We cannot exclude that other factors (e.g., diet) might play a role in this difference. Further studies are required to confirm these hypotheses.

Apparently two protocols are different that seem to help the Russians. First, the LBNP, developed by the Russians on their earlier space stations, is essentially a pair of pants that sucks fluids down to the legs, simulating the situation normally found on Earth, and thus reduces the fluids in the upper body sooner than landing. Second, doing exercises simulating lower weight loads apparently helps the Russians as well.

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Astronaut blood samples suggest long-term exposure to weightlessness causes brain damage

2:10 pm

New research comparing blood samples taken from five Russian astronauts before and after long term missions to ISS suggests that weightlessness can cause brain damage.

Published in JAMA Neurology, the new research looked at five male Russian cosmonauts. Each spent an average of 169 days in space. Blood samples were taken from each subject before leaving Earth, and then at three points after returning.

Five different blood-based biomarkers were measured, each known to correlate with some kind of brain damage. Three biomarkers in particular were found to be significantly elevated after the cosmonauts returned to Earth – neurofilament light (NfL), glial fibrillary acidic protein (GFAP), and a specific type of amyloid beta protein.

The researchers hypothesize the increases in NfL and GFAP levels may indicate a type of neurodegeneration called axonal disintegration. Elevated NfL levels are currently being investigated as a way of detecting the earliest stages of brain damage associated with Alzheimer’s disease.

It must be emphasized that the research did not find brain damage, only data within the blood samples that is often associated with brain damage. More research is required to determine if these biomarkers indicate the same thing in space as they do on Earth.

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New changes to the brain found from long space missions

8:38 am

Scientists have discovered a “significant increase” in the brain’s white matter that occurs after astronauts have completed long missions in weightlessness.

The team conducted brain MRIs of 11 astronauts before they traveled to the ISS, and then again one day after they returned. Scans were then performed at several interval across the following year. “What we identified that no one has really identified before is that there is a significant increase of volume in the brain’s white matter from preflight to postflight,” Kramer says. “White matter expansion in fact is responsible for the largest increase in combined brain and cerebrospinal fluid volumes postflight.”

These changes remained visible one year after spaceflight, which the researchers say indicates they could be permanent alterations. Past research has suggested that changes in the volume of cerebrospinal fluid (CSF) specifically could be a key driver of Visual Impairment Intracranial Pressure in astronauts. The authors of the new study also observed an increase in the velocity of CSF through the cerebral aqueduct, along with deformation of the pituitary gland, which they believe is related to higher intracranial pressure in microgravity.

The uncertainties for this work remain very large. For one thing, the sample (11 astronauts) is very small. For another, the permanence of this change is only suggested and remains unproven.

Nonetheless, this research adds to the growing body of research that suggests that long term weightlessness is generally not good for the human body. It also reinforces the desperate need for research into the effects of even a small amount of artificial gravity. To most efficiently design spacecraft that provide some form of centrifugal force as artificial gravity, we need to find out the minimum required. It could be providing only 10% or 30% Earth gravity could be sufficient. Or not. We just don’t know.

The engineering challenges however go up significantly the more gravity you need to create. For future interplanetary travel this information is critical.

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Astronaut treated for blood clot on ISS

9:08 am

In a first, an unnamed astronaut had been treated for a blood clot while on a six-month mission on ISS sometime in the last few years.

Ultrasound examinations of the astronauts’ internal jugular veins were performed at scheduled times in different positions during the mission. Results of the ultrasound performed about two months into the mission revealed a suspected obstructive left internal jugular venous thrombosis (blood clot) in one astronaut. The astronaut, guided in real time and interpreted by two independent radiologists on earth, performed a follow-up ultrasound, which confirmed the suspicion.

Since NASA had not encountered this condition in space before, multiple specialty discussions weighed the unknown risks of the clot traveling and blocking a vessel against anticoagulation therapy in microgravity. The space station pharmacy had 20 vials containing 300 mg of injectable enoxaparin (a heparin-like blood thinner), but no anticoagulation-reversal drug. The injections posed their own challenges – syringes are a limited commodity, and drawing liquids from vials is a significant challenge because of surface-tension effects.

The astronaut began treatment with the enoxaparin, initially at a higher dose that was reduced after 33 days to make it last until an oral anticoagulant (apixaban) could arrive via a supply spacecraft. Anticoagulation-reversing agents were also sent.

Although the size of the clot progressively shrank and blood flow through the affected internal jugular segment could be induced at day 47, spontaneous blood flow was still absent after 90 days of anticoagulation treatment. The astronaut took apixaban until four days before the return to Earth.

On landing, an ultrasound showed the remaining clot flattened to the vessel walls with no need for further anticoagulation. It was present for 24 hours after landing and gone 10 days later. Six months after returning to Earth, the astronaut remained asymptomatic.

What is not known is whether weightlessness caused the clot, or whether it would have occurred regardless. The former seems very possible as the astronaut had no history of such clots, and returned to normal almost immediately upon return to Earth. As noted at the link, more research is necessary, especially in anticipation of long interplanetary flights.

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Mice in space and kept in artificial gravity experience no harm to reproduction

11:43 am

The uncertainty of science: Male mice who spent thirty-five days on ISS but within a centrifuge that created 1 g of artificial gravity apparently experienced no damage to their ability to reproduce.

This project team developed a habitat cage unit (HCU) capable of being installed in the Centrifuge-equipped Biological Experiment Facility (CBEF) on the ISS. The mice were placed under artificial gravity or microgravity (by centrifugation). After their return to Earth, they were compared with a “ground control” raised on the ground for the same 35-day period. (Fig.1)

The joint team found that: [1] The sperm production ability and the sperm fertilizing ability of the mice returned to Earth were normal, compared to the ground control and, [2] offspring of the mice sent to outer space was healthy and there were no effects on their reproduction ability from their parents’ stay in outer space.

While this study suggests that some form of artificial gravity can possible mitigate some of the risks to reproduction in space, there are so many unknowns that it at this point it leaves more questions than it answers.

  • Would an artificial gravity less than 1 g accomplish the same thing?
  • Would no gravity cause damage? According to the study, this is not yet known.
  • What about insemination? Would it proceed with no problems in space?
  • What about female reproduction? Will artificial gravity mitigate issues for them?

I could go on. I almost wish they had done this experiment first in zero gravity, to see its effects, before proceeding to an artificial gravity environment.

Nonetheless, these results do suggest that reproduction in space will be possible, as long as an artificial gravity of some kind is provided.

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Faking gravity in space with a spinning table

2:38 pm

Researchers at the University of Colorado in Boulder are experimenting with the use of a rotating table to give space-farers short doses of artificial gravity in order to mitigate the negative consequences of weightlessness.

In a series of recent studies, the pair and their colleagues set out to investigate whether queasiness is really the price of admission for artificial gravity. In other words, could astronauts train their bodies to tolerate the strain that comes from being spun around in circles like hamsters in a wheel?

The team began by recruiting a group of volunteers and tested them on the centrifuge across 10 sessions.

But unlike most earlier studies, the CU Boulder researchers took things slow. They first spun their subjects at just one rotation per minute, and only increased the speed once each recruit was no longer experiencing the cross-coupled illusion. “I present at a conference and everyone says, ‘she’s the one who spins people and makes them sick,'” Bretl said. “But we try to avoid instances of motion sickness because the whole point of our research is to make it tolerable.”

The personalized approach worked. By the end of 10th session, the study subjects were all spinning comfortably, without feeling any illusion, at an average speed of about 17 rotations per minute. That’s much faster than any previous research had been able to achieve.

The idea is that you could install this rotating table on a interplanetary ship, and have its occupants periodically spend time on it to get their daily dose of gravity. This way you would not have to build a giant spinning spaceship.

The research has potential. The one question that remains unanswered and is probably central to this concept is how little gravity is needed to avoid the problems of weightlessness. Right now, we do not know. It could be for example that 30 minutes at 1/10 g could do the job. Or maybe 1 g for 2 hours. If the former the engineering challenges become minor. If the latter the problems are more difficult.

I am aware of only one centrifuge experiment ever done in weightlessness, on a Russian space station. They rotated a plant at a very tiny percentage of g’s and found it might help plants prosper in space. The data point however is too small, with no followup. This is the kind of research that should be going on on ISS, and is not.

Hat tip Marcus A.

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Germany to do partial gravity experiments using Zero-G airplane

8:53 am

In what might be the first human experiments in partial gravity, Germany has hired the Zero-G airplane for a series of flights testing how humans react in such conditions.

In the Partial G Campaign, the pilots fly three special parabolic shapes. So instead of zero-g or microgravity, one quarter, half and three quarters of Earth’s gravity will still be present. Passengers on board will therefore experience one quarter, half or three quarters of their own body weight – depending on the trajectory,” explains Stang.

The goal of these flights is to see what effect partial gravity has on human muscle control.

For humans to be able to move around and interact with their environment, they require finely tuned muscle movements, to walk around or ensure a secure footing, for instance. Under partial gravity, in particular, they must be able to effectively control their muscles via their neural pathways. If we are unable to do so, the risk of stumbling is dramatically increased. This applies to both humans on Earth and astronauts in space. However, partial gravity conditions appear to influence this neuromuscular control in challenging situations, increasing the astronaut’s risk of stumbling. Researchers at the University of Freiburg are investigating why this is so. The results are intended to reduce the risk to astronaut safety during missions to other planets, thereby resolving a fundamental safety issue in human physiological space exploration.

This is better than nothing, but it seems to me to be the least important thing to study in partial gravity. The Apollo astronauts clearly demonstrated that humans can adapt their muscle movements to partial gravity. What we must instead learn is whether partial gravity will eliminate bone loss, loss of cardio-vascular conditioning, spinal changes, balance problems, and the vision damage, all of which have been found to occur in weighlessness.

At the same time, it is probably impossible to study any of these latter issues during a short parabolic vomit comet flight. The Germans are doing what they can. Unfortunately, they might be the only ones doing anything in this area.

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Heavier astronauts more likely to have vision issues in zero-G

9:51 am

An analysis of the physical characteristics of astronauts who develop vision problems after long missions in weightlessness has found that heavier body weight increases the risk.

The research team examined data collected by NASA from astronauts who had made long-duration space flights (averaging 165 days). The data included the astronauts’ sex and pre-flight height, weight, waist and chest size, as well as information about post-flight eye changes. The findings were related to body weight, not body mass index. They found that none of the female astronauts analyzed—who weighed less than the males—returned to Earth with symptoms of SANS. To rule out sex differences as a cause for the disparity, the researchers also examined the men’s data separately. “Pre-flight weight, waist circumference and chest circumference were all significantly greater in those who developed either disc edema or choroidal folds. This was still true when only the male cohort was analyzed,” the researchers wrote. “The results from this study show a strong relationship between body weight and the development of ocular changes in space.”

That such small differences in weight can make such a difference suggests again that adding just a small amount of artificial gravity, rather than 1g, might mitigate these issues. No tests of this however have ever been done, mostly because the engineering is complex and expensive. For humans we would need to build a vessel large enough that any rotation would be unnoticed. If the vessel is small it must rotate faster and the body’s inner ear gets confused. However, if we only need to simulate a tiny amount of gravity the spin rate can be reduced, simplifying the engineering.

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Growing cucumbers in space

9:48 am

New research growing cucumbers on ISS has found that the roots of these plants grew in the direction of water in weightlessness.

Plant roots grow to find water, according to a process known as hydrotropism. Roots are also influenced by gravity and tend to grow downwards, called gravitropism. To find out whether gravity or water had the greater influence on root growth, investigators grew cucumber plants in the microgravity environment on board the International Space Station. In their experiments, water (or hydrotropism) had more influence in controlling root growth.

“We will be able to utilize roots’ ability to sense moisture gradients for controlling root growth orientation and efficiently growing plants in future space farms,” said Dr. Hideyuki Takahashi, senior author of the New Phytologist study.

You can read the full science paper here.

This might sound obvious, but it isn’t. Past plant growth experiments on Mir and ISS had tended to show that plant roots did not know where to grow in weightlessness, suggesting that they needed gravity to guide the roots to water. Because of this, later experiments in space provided the roots complicated engineering to guide the roots to the water.

This experiment shows that maybe that complex engineering is not necessary, or at least could be simplified a bit. At a minimum it is crucial information engineers will need to design any future gardens for interplanetary spaceships with long term weightlessness.

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Worm grows 2 heads on ISS

5:29 pm

The uncertainty of science: For reasons that are not yet understood, a flatworm fragment flown to ISS in a microgravity experiment regenerated with two heads.

But the most dramatic difference was a type of regeneration observed in one of the 15 worm fragments sent to the ISS. That worm returned to the scientists with two heads (one on each end of its body), a type of regeneration so rare as to be practically unheard of — “normal flatworms in water never do this,” Levin told Live Science. When the researchers snipped both heads off back on Earth, the middle portion regenerated into a two-headed worm again.

“And these differences persist well over a year after return to Earth!” Levin said. “Those could have been caused by loss of the geomagnetic field, loss of gravity, and the stress of takeoff and landing — all components of any space-travel experience for living systems going to space in the future,” he said.

The flatworms that flew in space showed other significant differences from the control group that stayed on Earth, further suggesting that for flatworms at least the environment of weightlessness causes more problems that were expected.

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ISS twin study suggests weightlessness stresses the body in unexpected ways

9:21 am

The first preliminary results from NASA’s comparison of Scott Kelly, who spent 340 days on ISS, and his twin brother Mark, who did not, suggests that weightlessness stresses the body’s genetic system in ways not previously measured.

Preliminary results are in from NASA’s unprecedented twin study — a detailed probe of the genetic differences between astronaut Scott Kelly, who spent nearly a consecutive year in space, and his identical twin Mark. Measurements taken before, during and after Scott Kelly’s mission reveal changes in gene expression, DNA methylation and other biological markers that are likely attributable to his time in orbit.

From the lengths of the twins’ chromosomes to the microbiomes in their guts, “almost everyone is reporting that we see differences”, says Christopher Mason, a geneticist at Weill Cornell Medical College in New York City. He and other project scientists reported the early results on 26 January in Galveston, Texas, at a meeting of scientists working in NASA’s Human Research Program. “The data are so fresh that some of them are still coming off the sequencing machines,” Mason says.

It remains unclear at this point the medical consequences of these genetic changes. The data from this first experiment is still too preliminary, and it only involves looking at two people, a sample that is obviously too small. Nonetheless, it is a beginning, and of some significance.

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Cause of vision problems in space pinpointed?

9:12 am

New research suggests that scientists have pinpointed the cause of the vision problems astronauts experience from long term weightlessness.

The new research showed that intracranial pressure in zero-gravity conditions, such as exists in space, is higher than when people are standing or sitting on Earth, but lower than when people are sleeping on Earth. The researcher’s finding suggests that the constancy of pressure on the back of the eye causes the vision problems astronauts experience over time.

More important, the research has also suggested a possible cure.

“The information from these studies is already leading to novel partnerships with companies to develop tools to simulate the upright posture in space while astronauts sleep, thereby normalizing the circadian variability in intracranial pressure, and hopefully eliminating the remodeling behind the eye,” said Dr. Levine, who holds the Distinguished Professorship in Exercise Sciences.

The researchers have continued studying whether it is possible to lower intracranial pressure by means of a vacuum device that pulls blood away from the head. They previously showed that a negative pressure box that snuggly fits the lower body can lower intracranial pressure when applied for 20-minute periods. They will soon be testing the effect of the lower body negative pressure device on eye remodeling when negative pressure is applied for eight-hour periods. “Astronauts are basically supine the entire time they are in space. The idea is that the astronauts would wear negative pressure clothing or a negative pressure device while they sleep, creating lower intracranial pressure for part of each 24 hours,” said first author Dr. Justin Lawley, Instructor in Internal Medicine at UT Southwestern and a researcher at the IEEM.

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The effect of weightlessness on the spine

9:04 am

New observations of astronauts before and after four to seven month long missions to ISS has found the back pain many astronauts experience appears to be caused by significant muscle atrophy.

The MRI scans indicated significant atrophy of the paraspinal lean muscle mass —which plays a critical role in spinal support and movement—during the astronauts’ time in space. The lean muscle, or “functional,” cross-sectional area of the lumbar paraspinal muscles decreased by an average of 19 percent from preflight to immediate postflight scans. A month or two later, only about two-thirds of the reduction had recovered. There was an even more dramatic reduction in the functional cross-sectional area of the paraspinal muscles relative to total paraspinal cross-sectional area. The ratio of lean muscle decreased from 86 percent preflight to 72 percent immediately postflight. At follow-up, the ratio recovered to 81 percent, but was still less than the preflight value.

In contrast, there was no consistent change in the height of the spinal intervertebral discs. Dr. Chang and coauthors write, “These measurements run counter to previous hypotheses about the effects of microgravity on disc swelling.” Further studies will be needed to clarify the effects on disc height, and whether they contribute to the increase in body height during space missions, and to the increased risk of herniated disc disease.

These results are very encouraging, because they indicate that the back problems seen are mostly attributable to weakened muscles, not actual spinal damage, and can therefore be more easily mitigated by new exercises while in orbit.

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More Junk Science and Journalism

11:46 am

I can’t stand it. I just can’t stand it. It keeps happening and I just can’t stand it.

Yesterday there was this absurd short news piece posted on the website of the so-called journal Science, “Apollo astronauts much more likely to die from heart disease”. describing a research paper published by one of Nature’s side journals, Scientific Reports. Before I even looked at the story I said to myself, “How can they possibly come to that conclusion considering the tiny number of humans who have ever traveled beyond Earth orbit? The sample will simply be too small to allow for any such finding.”

Then I looked at the article and found my instincts confirmed. As Steve Milloy noted on his very aptly named website, Junk Science,

Yes, the result is based on a total of three (3) cases of heart disease deaths of out seven (7) Apollo astronauts. Past the vanishingly small sample size and even smaller number of cases, heart disease is a natural disease of aging and the Apollo lunar astronauts were 10 years older than the other comparison groups.

To put it more bluntly, this was a garbage piece of very bad science. While it was somewhat embarrassing for a Nature journal to publish it, it was far more disgraceful for the journal Science to highlight it. I, however, don’t have to join these two peer-review journals and participate in their stupidity, and thus I made no mention of the story on Behind the Black, because it is my policy to not waste much time on bad science, unless I think that bad science is going to have bad repercussions.

Well the bad repercussions have arrived. Since yesterday, the following so-called news organizations have run with this story, without the slightest indication that they have faintest understanding of science, statistics, or plain common sense:
» Read more

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Vision problems from weightlessness

6:03 pm

This article provides an excellent review of the vision problems caused by long term exposure to weightlessness, including the efforts to study the problem on Earth.

Bottom line:

Before a human trip to Mars — a journey of six-to-nine months that NASA says it wants to achieve by the 2030s — researchers agree that VIIP [the name given to this problem] must be understood much better. VIIP could be the first sign of greater dangers to the human body from microgravity. “We’re seeing the visual and neural, ophthalmic manifestations of it,” Barratt said. “I’m fairly certain this is a bit more global than that.”

Richard Williams, the chief health and medical officer at NASA, agrees that what we do not know about VIIP still poses the biggest threat. Ironically, one of the only ways to get more knowledge is spend more time in microgravity. “The longer we stay in space, the more we’re going to learn,” Williams said.

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Kelly describes medical issues from weightlessness

8:50 am

In prepared remarks to a congressional subcommittee today, astronaut Scott Kelly described the medical problems he has experienced since returning from his 340 day mission on ISS.

Kelly claimed in these remarks that weightlessness caused permanent effects (which this news article decides to emphasize), but I think that might be an overstatement. None of the specific problems he experienced appear to be permanent ones, and in my interviews with Russian astronauts who stayed even longer on Mir they noted no permanent effects. One did say however that the recovery time tended to match the mission time, so that if you spent a year in space it took a year to completely recover. Kelly has only been back about three months, so his recovery is certainly not over yet.

Update: Kelly’s remarks were part of a hearing promoting legislation that would give astronauts lifetime medical coverage from the government. Thus, there is a bit of lobbying going on here.

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Liver damage from weightlessness?

11:28 pm

The uncertainty of science: Mice flown for almost two weeks on the last space shuttle mission in 2011 have shown evidence of the early symptoms of liver disease.

The mice spent time orbiting the Earth on the final space shuttle flight in 2011. Once they returned home, teams of scientists were allowed to share and study their internal organs.

Jonscher’s team found that spaceflight resulted in increased fat storage in the liver, comparing pair-fed mice on Earth to those on the shuttle. This was accompanied by a loss of retinol, an animal form of Vitamin A, and changes to levels of genes responsible for breaking down fats. As a result, mice showed signs of nonalcoholic fatty liver disease (NAFLD) and potential early indicators for the beginnings of fibrosis, which can be one of the more progressive consequences of NAFLD. “It generally takes a long time, months to years, to induce fibrosis in mice, even when eating an unhealthy diet,” Jonscher said. “If a mouse is showing nascent signs of fibrosis without a change in diet after 13 ½ days, what is happening to the humans?”

This result doesn’t prove that weightlessness causes liver damage. It only suggests that more research is needed, though the data from six month to year long missions suggest that the liver harm to humans is either non-existent or temporary.

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Injected stem cells cure osteoporosis in mice

9:22 am

Scientists have discovered that an injection of stem cells into mice with osteoporosis was able to completely cure them of the bone disease.

Researchers at the University of Toronto and The Ottawa Hospital had previously found a causal effect between mice developing age-related osteoporosis and a deficiency in mesenchymal stem cells (MSCs). One of the promising attributes of MSCs is that, while they can grow into different cells in the body just like other stem cells, they can be transplanted without the need for a match. “We reasoned that if defective MSCs are responsible for osteoporosis, transplantation of healthy MSCs should be able to prevent or treat osteoporosis,” says William Stanford, senior scientist at The Ottawa Hospital and Professor at the University of Ottawa.

To put this reasoning to the test, the scientists injected MSCs into mice with the condition. Six months later, which is one quarter of the life span of the animal, they observed a healthy functional bone in place of the damaged one. “We had hoped for a general increase in bone health,” says John E. Davies, co-author of the study. “But the huge surprise was to find that the exquisite inner ‘coral-like’ architecture of the bone structure of the injected animals – which is severely compromised in osteoporosis – was restored to normal.”

The importance of this discovery for space travel is that it might eventually allow scientists to use it to somehow prevent the loss of bone density during weightlessness.

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The first music video in zero gravity

10:30 am

Update: The music video itself has been pulled from youtube for copyright reasons that I don’t quite understand. However, the making of video is still available, and that will give you a pretty good feel for some of the stuff in the original piece.

I was going to make this an evening pause, but then decided it shouldn’t wait. This music video, by OK-Go, is unique and somewhat historic, as it I think is the first to have been done in zero gravity, using an airplane to fly parabolic arcs. It demonstrates clearly the fantastic and as present almost unimaginable possibilities of dance in weightlessness, as it also might be the first time that professional dancers, the two women, are given a chance to do moves in microgravity.

Be sure to also watch the making of video below the fold. And go here for the story behind the video.


» Read more

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Using fish to study bone loss in weightlessness

9:04 pm

A Japanese experiment on ISS, comparing the development of fish in weightlessness with those on the ground, has provided` scientists more information about bone density loss in weightlessness.

Akira Kudo at Tokyo Institute of Technology, together with scientists across Japan, have shown that medaka fish reared on the International Space Station for 56 days experienced increased osteoclast activity – bone cells involved in the re-absorption of bone tissue – likely leading to a subsequent reduction of bone density. They also found several genes that were upregulated in the fish during the space mission. The team generated fish with osteoclasts that emit a fluorescent signal. They sent 24 fish into space as juveniles, and monitored their development for 56 days under microgravity. The results were compared with a fish control group kept on Earth.

Kudo and his team found that bone mineral density in the pharyngeal bone (the jaw bone at the back of the throat) and the teeth of the fish reduced significantly, with decreased calcification by day 56 compared with the control group. This thinning of bone was accompanied by an increase in the volume and activity of osteoclasts. The team conducted whole transcriptome analysis of the fish jaws, and uncovered two strongly upregulated genes (fkbp5 and ddit4), together with 15 other mitochondria-related genes whose expression was also enhanced. Reduced movement under microgravity also has an influence. The fish began to exhibit unusual behavior towards the latter stages of their stay in space, showing motionless at day 47.

What the data mostly confirms is that long-term weightlessness is a bad thing for the development of bones, and not just in humans. Whether scientists can use these results to counter these harmful effects is not clear, however.

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Growing and eating lettuce on ISS

8:59 am

Astronauts are about to eat a crop of romaine lettuce that they have grown entirely from seed on ISS.

The story is important as it indicates that the engineering to grow plants in space is continuing to improve. The article however is very wrong when it says that this will be the first salad grown and eaten in space. Russian astronauts have been working on this problem on their space stations since the 1970s, and in at least one case — which was captured on video almost a decade ago — have eaten space-grown lettuce. (I wrote about this event for Air & Space back in 2003.)

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3D printed items made in space come back to Earth

11:00 pm

NASA today released a video of engineers unpacking a box of 3D parts that had been printed on ISS and then returned to Earth for testing.

Some more details here.

The goal, Bean continued, is for NASA to develop a database of mechanical properties to see if there’s any difference in mechanical strength between identical items made in space and on Earth. During the interview last month, Bean said that while NASA didn’t yet have any hard data, there had been initial indications from videos made on the space station, that the plastics used in the 3D printing there had “adhered differently” than those in the terrestrial test. “The astronauts trying to get the parts off the plate,” Bean said, found that the plastic “seemed to be a little more stuck than on the ground.” He said that while it was too early to tell if that was actually true, his guess was that if so, “it may be due to a lack of convection in zero-gravity.”

Understanding the engineering issues of 3D printing in space will make it possible for crews to carry far less cargo on long interplanetary journeys. Instead, they would carry a much smaller amount of raw material, which they could use to manufacture items as needed, then recycled.

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